effect of dietary and animal factors on milk fatty acids composition of grazing dairy cows: a review

in pasture-based milk production systems, using available farm resources in order to reduce feeding costs, the composition and functional properties of dairy cows’ milk are of considerable importance to the dairy farmer, manufacturer and consumer. basically, there are three options for altering the composition and/or functional properties of milk: 1) cow nutrition and grazing management, 2) cow genetics and 3) dairy manufacturing technologies. at the farm levels, manipulation of milk composition only occurs when it is perceived to be more profitable, normally, processing options are the option most considered. nevertheless, opportunities exist for manipulation of milk composition on the farm to improve the human and physiological properties of milk and dairy products, such as enhanced concentrations of conjugated linoleic acid (cla), or to improve its milk fatty acids (fa) composition for more efficient processing into a range of dairy products. this review considers the effect of dietary (pasture feeding, lipid feed supplements, seasonal and regional variations) and animal (breed, stage of lactation, parity and animal to animal) factors on milk fa composition of grazing dairy cows. furthermore, it highlights the relevance that these factors, in the context of an integrative-view, might play on the sustainability of pasture-based milk production systems in humid areas in terms of milk differentiation and higher added value which profit would be directly reached for the milk producer on the farm.